libvirt users - May 2011 - libvirt boots from Knoppix-CD but not Debian-CD

Debian Squeeze, libvirt 0.8.3, qemu-kvm 0.15.5

After configuring the cd image the bios screen shows:
(tested with virsh, virt-install and virt-manager)

Starting SeaBIOS (version 0.5.1-20110523_174945-brahms)

Booting from CD-Rom
65MB medium found (bzw. whatever size)
Boot failed: Could not read from CDROM (code 000c)
...

the cd images (debian6-cd1, debian6-netinst, debian6-buisnesscard) have
the correct md5sum an can be mounted, they simply do not boot. On the
other hand, a recent knoppix ISO works well. Tested countless times. All
access rights are 777.

Only special feature: the host is a minimal installation done with
debootstrap and contains not much else than libvirt, virt-manager and
lxterminal.

I am out of wit. Any ideas?

-- 
Christian Brandt

 life is short and in most cases it ends with death
 but my tombstone will carry the hiscore

Based on further experiments I think you can not boot any debian cd with
seabios/kvm/libvirt solution, am I right?

-- 
Christian Brandt

 life is short and in most cases it ends with death
 but my tombstone will carry the hiscore

Problem solved, the solution:

Don't trust labels on disks. They often mix up architectures.

Don't trust labels on computers. They often do not only mix up
architectures but also send you into login into a virtual engine instead
of the real engine.

Don't trust jigdoed ISO-Images. Stupid people will have done stupid
things to the data before mkisofs, including but not limited to mixing
up architectures.

Final though: Even if your internet line is only 128kBit always download
official images.

-- 
Christian Brandt

 life is short and in most cases it ends with death
 but my tombstone will carry the hiscore